Power components with a high current capacity are necessary for modern applications. With semiconductor technologies that can switch very high power levels, high current densities and the heat resulting from power dissipation must be discharged from the chip to the environment using appropriate construction and connection technology. Conventional connecting or bonding techniques are expensive and time-consuming, and represent, in particular, a bottleneck for the current to be discharged from the chip. Good thermal contacting has hitherto been accomplished using a chip rear side soldered over a large surface area. Mounting techniques that allow good electrical and thermal contacting, for example by mounting the chip on a large surface on both sides, are used in this context.
A metal lead frame, which can be manufactured inexpensively and is produced, for example, as a stamped grid, is usable in particular as a connecting device for contacting the semiconductor component to a further component of the subassembly. The various terminal regions or contact regions of the semiconductor component can be soldered directly onto, for example, inner ends of the connecting strips of the lead frame. A particular disadvantage of using such metal lead frames, however, is the generally greater expansion of the metal as compared with the silicon of the semiconductor component, so that thermal stresses and defects can occur, as a result of the temperature ranges achievable during operation, in the metal connecting strip applied on the chip surface and/or at its interface with a contact layer made of solder or conductive adhesive.
Also known are materials with which double-sided solder joins can be made, for example direct-bonded copper (DBC) ceramics. These specially treated ceramics or thermal-clad substrates are, however, generally costly and complex in terms of manufacture.